Grouping data by MONTH on DATETIME column in SQL Server

I have a table Employee which has the columns Id, Date of joining and Name

Date of joining is a DATETIME column.

I want to know how many users have joined in the month of October?

If you're just looking for October regardless of the year, then the easy way would be to just COUNT the records from that month:

SELECT COUNT(*) AS NumberOfJoiners FROM Employee WHERE MONTH(DateOfJoining) = 10;

or

SELECT COUNT(*) AS NumberOfJoiners FROM Employee WHERE DATEPART(MONTH, DateOfJoining) = 10;

If you want to group by year, then you'll need a group by clause, otherwise October 2013, 2014, 2015 etc would just get grouped into one row:

SELECT 
  DATEPART(YEAR, DateOfJoining) AS YearOf Joining, 
  COUNT(*) AS NumberOfJoiners 
FROM Employee
WHERE DATEPART(MONTH, DateOfJoining) = 10
GROUP BY DATEPART(YEAR, DateOfJoining);

StackExchange Database Administrators Q#81823, answer score: 7